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Oct. 2, 2012 -- A new study suggests that many patients may not benefit from beta-blockers, one of the most commonly prescribed medications for heart disease.

Beta-blockers slow down the heart. They're life savers for people with heart failure and others with fragile hearts badly damaged by heart attacks. There's no question that beta-blockers benefit such people.

But doctors also give beta-blockers to people whose hearts aren't so fragile, including:

People at high risk of heart disease

People with partially blocked arteries (coronary artery disease, or CAD) but who have not had a heart attack

Heart attack survivors, who should get at least three years of beta-blocker therapy, according to guidelines from the American College of Cardiology and the American Heart Association.

"In all these three subgroups of patients, there is no benefit of using beta-blockers," says Sripal Bangalore, MD, director of the cardiovascular outcomes group at the NYU School of Medicine.

Bangalore says recommendations for beta-blockers are based mostly on data collected two decades ago. Since then, treatment of heart attack and CAD patients has greatly improved.

"Now we immediately open their heart blockages up and give them new medicines like statins," Bangalore says. "If much of the heart muscle is already dead and there are a lot [heart rhythm problems], beta-blockers might be best. But in [the] modern patient, those things might not be there."

Beta-Blocker Study

Bangalore and an international team of researchers compiled medical records for 44,708 people who had suffered a heart attack, CAD without heart attack, or who were at high risk of heart disease.

After four years, they looked at whether patients given beta-blockers were less likely to die of heart disease or to suffer a heart attack or stroke.

Bottom line: They were not. Even when the researchers compared patients with the same risk factors for heart disease, those taking beta-blockers did not have better four-year results.

"We have shown in our study that if you have a heart attack and take beta-blockers for a year, you probably will benefit," Bangalore says. "But the question is, how long after a heart attack would beta-blockers offer a benefit? The European Union says use these drugs long-term only in patients with heart failure. American guidelines say to keep taking them for at least three years after a heart attack."

Those U.S. guidelines remain firmly in place, says William A. Zoghbi, MD, president of the American College of Cardiology.

Zoghbi notes that the Bangalore study is not a randomized clinical trial -- the gold standard of study design -- and by itself isn't enough evidence to change treatment guidelines.

Indeed, cardiologist David A. Friedman, MD, chief of heart failure services at North Shore-Long Island Jewish Hospital in Plainview, N.Y., says he's not going to change the way he treats heart attack and CAD patients.

"Beta-blockers have stood the test of time by decreasing [chest pain], by decreasing blood pressure and drive on the injured heart, and by letting the heart have time to heal," Friedman says. "I am not changing my practice, but this study and others have opened a new set of questions that need answers."

Who Needs Beta-Blockers, and for How Long?

Heart attack patients have one major question about beta-blockers.

"The most common question I get is, 'How long do I have to stay on the beta-blockers, doc?'" Friedman says. "We say, likely indefinitely, because you improve heart [function]."

Friedman notes that people differ widely in their response to beta-blockers. Zoghbi says doctors who prescribe beta-blockers must pay close attention to a patient's condition.

"The important thing is to make sure we control blood pressure," Zoghbi says.

Beta-blockers have major side effects, which can include diarrhea, stomach cramps, fatigue, depression, nightmares, and sexual dysfunction. A 2006 study found that one year after having a heart attack, only 45% of patients were still taking their beta-blockers.

"This is really where a discussion between a patient and the health care team is crucial," Zoghbi says. "Compliance is a significant issue. If patients are not tolerating a medication, we have to think of alternatives to control symptoms or decrease risk.”

The Bangalore study appears in the Oct. 3 issue of the Journal of the American Medical Association.